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Using Overdrive - How and When?
Yahoo Message Number: 153194
I'm "gearing up" to take a trip from Las Cruces, NM to Bend, OR and then probably to the Oregon Coast.

You'll have to forgive my "ignorance," but my 1998 Lazy Daze has an E-450 with an "overdrive" option.  Since I have only driven it last winter to Puerto Penasco (flat terrain) I haven't used the option.  However, driving to Oregon will be somewhat different.

I tried to look up the operation of the overdrive with no success.

Could someone please explain to me the operation of the overdrive (in layman's terms) and outline how and when I should use it.

Thanks,

Cheryl 1998 Lazy Daze (26.5 mid-bath) 2002 Honda CR-V
Cheryl (a.k.a. Desert Diva)
1998 Lazy Daze (26.5 mid-bath)
2002 Honda CR-V
Re: Using Overdrive - How and When?
Reply #1 –
Yahoo Message Number: 153196
Cheryl,
 The transmission works by changing how power is applied to the rear wheels.  In the low gears, multiple engine revolutions are used to turn the driveshaft once.  This multiplies the torque applied to the rear wheels when it is needed to get the motorhome moving.  Typically in "high" gear, one engine revolution is turned into one driveshaft revolution.  In "overdrive" less than one engine revolution is used to turn the driveshaft one full revolution.  This is great for fuel economy since the engine is running slower, but less torque is available to push the motorhome up a grade.  If overdrive is enabled and the engine cannot keep the speed up a hill, the system will sense that and downshift to a lower gear. In hilly country, the transmission will tend to "hunt", frequently shifting gears up and down.  This is hard on the transmission and will cause it to heat up.  The button on the end of the shift lever can be used to lock-out using the overdrive gear.  This loses a little fuel economy, but is much better for the transmission.

HTH, Art
Art and Barbara
Settled in Atterdag Village of Solvang
2015-2022 fulltime in a 2016 Tiffin Allegro Bus 37AP
2002-2015 2002 LD MB
Art's blog
Re: Using Overdrive - How and When?
Reply #2 –
Yahoo Message Number: 153198
The previous owner of my  2003 LD MB told me not to use O/D in stop and go traffic,  like in town and  engage O/D on Freeway driving.   Escondido        John
John in Escondido,  CA
Re: Using Overdrive - How and When?
Reply #3 –
Yahoo Message Number: 153199
Well the overdrive button disengages the overdrive it doesn't engage it.. Also the only time it has any effect is when the automatic transmission is in high gear. While the transmission is shifting up or down thru 1st to 4th gear it has no effect. So I am not sure there would be any effect at all in stop and go traffic..

Note the "ovdrdrive" switch is an "overdrive cancel" switch.. It is used to lock out overdrive on steep grades or when hauling heave loads. It can also be useful on downgrades as it locks up the torque converter and gives you some engine braking. It was replaced in later years with a tow/haul switch.. which performs similar functions..

Larry Wade could give better explanation I am sure..
Garry
Re: Using Overdrive - How and When?
Reply #4 –
Yahoo Message Number: 153200
'The previous owner of my 2003 LD MB told me not to use O/D in stop and go traffic,  like in town and engage O/D on Freeway driving.''  John

If you have not already heard me say this, the Factory Owner's Manual is the bible when it comes to operating your E450.
I suggest reading your LD's Ford owner's Manual's section on transmission usage,  all in there and there is nothing about not using overdrive in stop and go driving.
Normally in this situation, the transmission rarely engages 4th gear. I usually keep the gear selector in Drive and leave it there except for long up and downgrades, where downshifting is appropriate.

The 4L100 transmission is computer controlled, programmed by  Ford Factory engineers who know a lot more about the driveline capability than any of us..
I have found it does a good job of handling the gears, in most situations.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze
Re: Using Overdrive - How and When?
Reply #6 –
Yahoo Message Number: 153204
On our recent cross country trip towing our sailboat, I was surprised at how well our LD,(1997 23.5 TK), pulled the load. Now the original owner had installed the complete Banks engine and transmission kit, and the additional torque was noticeable.  The transmission would occasional,(or I would manually), kick out of overdrive on an extended grade. I also would kick it out of overdrive when coming down long grades to keep the rig speed in check. Only time she shifted into a lower gear was pulling up the grades on I-8 westbound out of El Centro.  I thought about staying on I-10 to PHX and pick up Hwy-60 to I-215 and I-15 home.  Next time that will be the route. I was also glad to see the scan gauge showed a maximum coolant temperature of 209 degrees. 99% of the time the coolant temperature ran between 197 to 204 degrees, regardless of towing the boat or not.

Don
Re: Using Overdrive - How and When?
Reply #7 –
Yahoo Message Number: 153205
"99% of the time the coolant temperature ran between 197 to 204 degrees, regardless of towing the boat or not."

--- Are these temperatures seen when just running at "highway speeds", i.e., around 60 or so, on the flat or just when pulling hills? What were the ambient temperatures when these coolant numbers were registering?

I'm curious because my 2003 TK regularly runs between 191 and 193 degrees on a "flat" road at 60 mph; if the weather is very cool and/or rainy, it will often run at 188 degrees. The highest coolant temperature that I've seen indicated on the ScanGauge is 206 degrees when pulling long, steep hills (no toad) in warm weather.

I would think that with the increased air flow provided by a Banks system, your engine would run *cooler* than your numbers indicate?

Joan
2003 TK has a new home
Re: Using Overdrive - How and When?
Reply #8 –
Yahoo Message Number: 153206
FYI. On newer models of the E-450, the tow/haul mode is a very useful tool. When pushed in the tranny downshifts to aid braking in normal driving as well as mountain driving. I leave mine on most of the time for this reason. MPG reduction is minimal if any.
James Allen Jackson
Re: Using Overdrive - How and When?
Reply #9 –
Yahoo Message Number: 153221
Ambient temperature ran between 60 degrees to a little over 100 in the desert.  Most of the time we had between 85 to 95 degrees while driving.  Could be a difference in the thermostats installed.  Too cool can be an issue, the computer thinks the engine is still cold and gives a rich'er mixture, like still running with a partial choke on like in the old carburetor days.  My engine has the Banks system on the computer and exhaust, and the intake is stock with a K & N filter installed. Just had the engine oil and transmission fluid and filter changed this morning. Transmission fluid was good, no evidence of having run hot, and the pan was clean. So it gave me a good indication the transmission cooler is adequate, and evidently the running temperature is OK.

Don
Re: Using Overdrive - How and When?
Reply #10 –
Yahoo Message Number: 153232
I like what Larry had to say.
 For what it's worth, the button on my gear selector lever is not an overdrive button as I understand it.  It engages or disengages the tow/haul programming, which tells the transmission when to shift, and where.  My rig is a 2008.  It may be different on Cheryl's rig.  For the vast majority of my driving, as I am pulling a TOAD, I put the trans in the Tow/Haul mode as recommended in the manual.  I then put the selector in D and just drive.  The transmission programming does all that is needed.
 There is one exception to this.  If I am descending a long mountain grade, I will pick a gear based on the length and steepness of the grade.  I do this at the top, after slowing to the appropriate speed.  The transmission can then gently go into the gear I choose and I can ease down the hill with (usually) minimal braking and moderate speeds.  I have tried using the automatic function to manage my speed (at the top, foot off the gas, brake to the speed you want then tap the brake again while in the tow/haul function, which sets the upper speed for the system to maintain).  It sometimes does a nice job, but too often, it allows the speed to get too high, resulting in a downshift that takes me over 5000 RPM, my mental "yellow line".  That is the only time I override the automatic function.

Ken F in WY
'08 MB
Re: Using Overdrive - How and When?
Reply #11 –
Yahoo Message Number: 153233
On my older 2001 LD the button on the shift lever does turn O/D on and off. That's all it does, there is not a tow/haul function. I find that when I am towing my toad it is best to select 2nd gear at the top of the hill and maintain a low speed downhill with occasional brake usage. The transmission is not as "smart" as the later models, but maybe that means less to break down.

bobmoore14
Re: Using Overdrive - How and When?
Reply #12 –
Yahoo Message Number: 153234
To the best of my knowledge, the function of the button the the Ford van's shift lever was "Overdrive Off" up through 2004; in 2005 it changed to "Engage Tow/Haul".

Andy Baird
Andy Baird
2021 Ford Ranger towing 2019 Airstream 19CB
Previously: 1985 LD Twin/King "Gertie"; 2003 LD Midbath "Skylark"
Re: Using Overdrive - How and When?
Reply #14 –
Yahoo Message Number: 153238
Hi Joan, Thanks for the link to the overdrive article, I understand it much better now. I have a question, though.
I tow a very light hatchback, manual transmission Hyundai Accent, it weighs under 2000 lbs (at least empty
Re: Using Overdrive - How and When?
Reply #15 –
Yahoo Message Number: 153239
I would be interested to hear thoughts on the use of overdrive while towing. I keep overdrive on while towing my Jeep on flat roads. Always turn it off when descending or climbing hills. Cuts down on engine wear and fuel consumption. Going to read the manual to see if Ford thinks this is okay.

bobmoore14
Re: Using Overdrive - How and When?
Reply #16 –
Yahoo Message Number: 153241
Another excellent source from Professor Taylor. Thanks!

Chris
Formerly: 2002 30' IB
Re: Using Overdrive - How and When?
Reply #18 –
Yahoo Message Number: 153243
Exactly what I do on our '02. From my experience, there is no need to shut OD off when climbing hills as the tranny automatically downshifts as needed.

Chris
Formerly: 2002 30' IB
Re: Using Overdrive - How and When?
Reply #19 –
Yahoo Message Number: 153245
I don't tow, but I can't see any reason for not leaving "overdrive" on (it's the "default" transmission setting; 4th gear) when driving down a flat highway, towing or not. The engine works less hard (lower RPMs) and you may use a few tablespoons less of gas. ;-)

(Others do the same) I disengage OD (2003 with a 4R100 4-speed; no "Torq-shift") when climbing hills or grades and when descending the same; this helps to control downhill speed. I can hear (and feel; many years of "seat of the pants" driving!) the engine, and if the transmission even hints that it's starting to "hunt" or lug, OD is clicked off. If the grade is very steep, I shift into 2nd or 1st at the top (or bottom); shifting into an appropriate gear *before* a steep grade, particularly when descending, is a lot easier on the engine and the driver than careening around hairpin curves down the mountain, smoking the brakes, and swearing!

Frankly, I wish that the rig had a manual transmission; I still reach for the clutch and the floor shift!

This chart may be helpful for those who have the 4R100 transmission:

4R100 TRANSMISSION RATIOS

1st - 2.71 : 1 2nd - 1.54 : 1 3rd - 1.00 : 1 4th (OD) - 0.71 : 1 R - 2.88 : 1

As ever, YMMV.

Joan
2003 TK has a new home
Re: Using Overdrive - How and When?
Reply #20 –
Yahoo Message Number: 153246
"After reading the article I'm thinking this is indeed not hard on the LD transmission, which is what I thought previously. Do you or others agree this is ok? I guess it's more an opinion than a question that I'm after."

Bonnie

For normal driving, leave it in Drive. That's how it was designed to work.

Larry
Larry
2003 23.5' Front Lounge, since new.  Previously 1983 22' Front Lounge.
Tow vehicles  2020 Jeep Wrangler Rubicon, 2001 Jeep Cherokee
Photo Collection: Lazy Daze